As is known, a centrifugal pump develops hydraulic pressure by rotational kinetic energy to transport a fluid. If the fluid includes abrasive particles, such as slurries produced in the mining industry, centrifugal pumps for pumping those slurries exhibit a tendency of excessive wear on various areas of the pump. For example, in U.S. Pat. No. 5,489,187 (Ray) which is assigned to the same assignee as the subject invention, and whose disclosure is incorporated by reference herein, there is disclosed and claimed an impeller pump including a seal cavity in the high pressure or rear region of the pump, with the seal cavity including a vane structure to flush or clear out debris (e.g., abrasive particles) and entrained air bubbles in the fluid being pumped (the “pumpage”).
Another area of a centrifugal pump which is subject to abrasive wear is in the suction area of the centrifugal pump. In particular, within the centrifugal pump during pumping of an abrasive fluid, such as a slurry, the abrasive fluid tends to recirculate from the higher pressure discharge zone to the lower pressure suction inlet due to open clearances between the pump's casing and the pump's rotating impeller. The highest wear zone within the pump typically occurs where the impeller running clearances are closest to the stationary casing of the pump. The grinding of suspended particles against the adjacent surfaces cause pump components to erode. As is known the pump's running clearances are important to the operating performance and integrity of the pump. As this running clearance zone erodes from abrasion, pump components degrade causing the need for replacement and also results in the pump's operating performance to decline.
Thus, a need exists for a centrifugal pump which eliminates or greatly reduces the tendency of the pump to abrade at the close running clearances within the pump at the suction (low pressure) side of the pump. The subject invention addresses that need. In particular, as will be described in detail later, the subject invention makes use of deflector vanes on the suction side of the pump, e.g., on a wear plate mounted in front of the front face of the impeller and which protrude into the recirculation zone. Those deflector vanes interact with the rotating impeller's pump-out vanes located on the front face of the impeller, to thereby expel the abrasive particles and stop them from collecting and eroding the running clearance at the suction inlet. In addition, the deflector vanes tend to break any fluid vortices produced and alleviate the swirling wear against the stationary zone. This effect also slows particles from migrating and collecting at the close running clearance and thus stops or minimizes erosion in this zone. Thus, with the subject invention the hydrodynamic interaction between the front impeller vanes and the deflector vanes creates a dynamic seal that removes the particles from this zone and alleviates surface wear around the running clearances. This action maintains the operating performance and eliminates the need to replace wear parts as frequently. As such, the subject invention reduces the amount of wear on a critical centrifugal pump component, to allow longer part-life, all the while maintaining pump performance.
All references cited and/or identified herein are specifically incorporated by reference herein.